A biomimetic enhanced chiral honeycomb structure

Abstract

This invention relates to the field of honeycomb structure technology, specifically to a biomimetic reinforced chiral honeycomb structure. The structure comprises multiple periodically arranged chiral honeycomb basic units, each consisting of a ring and multiple ligaments connecting the rings. At least some of the ligaments have circular biomimetic reinforcing nodes, the diameter of which is larger than the thickness of the ligament and is integrally connected to it. This invention simulates the localized reinforcement structure of the enlarged bamboo nodes in *Phyllostachys edulis* by locally setting biomimetic reinforcing nodes in the ligaments, significantly improving the bending stiffness and load-bearing capacity of the ligaments with relatively low added mass, resulting in higher plateau stress in the structure. This invention has a simple structural form, is relatively easy to manufacture, and can be extended to other bending-dominant honeycomb structures.

Description

Technical Field

[0001] This utility model relates to the field of honeycomb structure technology, and more specifically, to a biomimetic enhanced chiral honeycomb structure. Background Technology

[0002] Chiral honeycomb structures are a commonly used type of buffer and energy-absorbing structure. They typically consist of circular rings and ligaments connecting the rings, arranged periodically to form a honeycomb configuration with chiral characteristics. Due to their lightweight, designable deformation modes, and good buffer and energy absorption capabilities, these structures show promise for applications in aerospace, transportation, and equipment protection.

[0003] However, conventional chiral honeycomb structures, as typical in-plane bending-dominated structures, rely primarily on slender ligaments as their load-bearing components when subjected to compression, impact, or bending loads. These ligaments are prone to bending deformation, thus limiting the structure's plateau stress, load-bearing capacity, and energy absorption capacity. Directly increasing the overall thickness of the ligaments or increasing the amount of material used can improve stiffness, but it would significantly increase the structural mass, weakening the lightweight advantages of honeycomb structures.

[0004] In existing technologies, to improve the energy absorption performance of honeycomb structures, chiral honeycombs are typically combined with concave honeycombs, re-entry honeycombs, or other types of honeycombs to form hybrid honeycomb or coupled metamaterial structures. While this approach can improve structural performance to some extent, it often introduces more configuration units and connections, increasing the geometric complexity, manufacturing difficulty, and manufacturing cost of the structure. Furthermore, it is not conducive to simple and scalable performance control based on existing chiral honeycomb configurations. Utility Model Content

[0005] The purpose of this application is to provide a biomimetic enhanced chiral honeycomb structure and to solve the problems mentioned above.

[0006] The present invention adopts the following solution:

[0007] A biomimetic enhanced chiral honeycomb structure includes multiple chiral honeycomb basic units arranged periodically in the in-plane direction. Each chiral honeycomb basic unit includes a ring and multiple ligaments connected to the ring. Adjacent chiral honeycomb basic units are connected by the ligaments. At least a portion of the ligaments are provided with circular biomimetic enhancement nodes to form a localized reinforcement structure for absorbing energy. The diameter of the circular biomimetic enhancement nodes is larger than the thickness of the ligaments, and the circular biomimetic enhancement nodes are integrally connected to the ligaments.

[0008] Furthermore, the chiral cellular basic unit includes a ring and four ligaments tangent to the outer periphery of the ring. The four ligaments are equally spaced along the circumference of the ring and are used to connect the rings of adjacent chiral cellular basic units.

[0009] Furthermore, each of the ligaments is provided with at least one of the circular biomimetic reinforcement nodes.

[0010] Furthermore, each of the ligaments is provided with a plurality of circular biomimetic reinforcement nodes at equal intervals.

[0011] Furthermore, the number of nodes, node diameter, and distribution position of the circular biomimetic reinforcement nodes are configured as adjustable parameters to regulate the platform stress, specific energy absorption, and overall load-bearing capacity of the biomimetic reinforced chiral honeycomb structure.

[0012] Beneficial effects:

[0013] Bionic reinforcement nodes can improve the bending stiffness and load-bearing capacity of ligaments with relatively low added mass, enabling the structure to achieve higher plateau stress while maintaining a similar compaction strain to that of a typical chiral honeycomb structure. By adjusting the number, diameter, and distribution of nodes, the plateau stress, specific energy absorption, and overall load-bearing capacity of the honeycomb structure can be flexibly controlled, facilitating parametric design for different protection requirements. This reinforcement method does not require combining chiral honeycombs with other complex honeycomb configurations, resulting in a simple structure, lower manufacturing difficulty, and applicability to other bending-dominant honeycomb structures. Attached Figure Description

[0014] Figure 1 This is a structural diagram of *Qiong bamboo*.

[0015] Figure 2 This is a schematic diagram of a biomimetic enhanced chiral honeycomb structure according to an embodiment of the present invention;

[0016] Figure 3 This is a front view schematic diagram of a biomimetic enhanced chiral honeycomb structure according to an embodiment of this utility model;

[0017] Figure 4 This is a schematic diagram of a biomimetic enhanced chiral honeycomb structure according to an embodiment of the present invention, wherein each ligament has two circular biomimetic enhanced nodes;

[0018] Figure 5 This is a frontal view of a biomimetic enhanced chiral honeycomb structure according to an embodiment of the present invention, wherein each ligament has two circular biomimetic enhanced nodes;

[0019] Figure 6This is a schematic diagram of a biomimetic enhanced chiral honeycomb structure according to an embodiment of the present invention, wherein each ligament has three circular biomimetic enhanced nodes;

[0020] Figure 7 This is a frontal view of a biomimetic enhanced chiral honeycomb structure according to an embodiment of the present invention, wherein each ligament has three circular biomimetic enhanced nodes;

[0021] Figure labels: 1. Ring; 2. Ligament; 3. Circular biomimetic reinforcement node. Detailed Implementation

[0022] Combination Figures 2 to 7 As shown, this embodiment provides a biomimetic enhanced chiral honeycomb structure, which includes multiple chiral honeycomb basic units arranged periodically in the in-plane direction. Each chiral honeycomb basic unit consists of a ring 1 and multiple ligaments 2 connecting the ring 1. Multiple chiral honeycomb basic units are periodically arranged and interconnected via the ligaments 2 to form a complete honeycomb structure. In this embodiment, the chiral honeycomb basic unit adopts a four-ligament configuration, meaning each chiral honeycomb basic unit includes a ring 1 and four ligaments 2. The four ligaments 2 are tangent to the outer periphery of the ring 1 and are evenly spaced along the circumference of the ring 1. Each ligament 2 is connected to the ring 1 of an adjacent chiral honeycomb basic unit. This four-ligament chiral honeycomb basic unit has the advantages of good symmetry and stable deformation modes, and is the preferred configuration of this invention.

[0023] At least a portion of the ligament 2 is provided with circular biomimetic reinforcing nodes 3, which serve to form a localized reinforcing structure for energy absorption. The diameter d of the circular biomimetic reinforcing node 3 is larger than the thickness T of the ligament 2. This dimensional relationship ensures that the circular biomimetic reinforcing node 3 can form an effective reinforcing area locally within the ligament 2. Simultaneously, the circular biomimetic reinforcing node 3 and the ligament 2 are integrally molded, eliminating any obvious interface or weak connection areas between them, thus ensuring effective load transfer between the circular biomimetic reinforcing node 3 and the ligament 2.

[0024] The circular biomimetic reinforcement node 3 simulates the localized reinforcement structure of the enlarged bamboo nodes of *Phyllostachys edulis*. Combined with... Figure 1 As shown, *Phyllostachys edulis* is a type of bamboo whose nodes exhibit a swollen shape. This structure possesses excellent mechanical properties in nature, providing effective local reinforcement while maintaining lightweight design. This invention draws upon this biological structural reinforcement principle, incorporating circular biomimetic reinforcement nodes 3 on the ligament 2 to simulate the local reinforcement effect of the swollen nodes of *Phyllostachys edulis*. Through the arrangement of these circular biomimetic reinforcement nodes 3, the ligament 2 achieves a significant improvement in local stiffness and strength while maintaining overall lightweight design.

[0025] In one specific implementation of this embodiment, a circular biomimetic reinforcement node 3 is provided on each ligament 2. This circular biomimetic reinforcement node 3 is located near the middle position along the length of the ligament 2, which is a stress concentration area and a weak point prone to buckling deformation. Placing the circular biomimetic reinforcement node 3 at this location can effectively improve the stiffness and strength of the critical load-bearing area. When the structure is subjected to compressive, impact, or bending loads, the increased cross-sectional size at the location of the circular biomimetic reinforcement node 3 significantly enhances its bending stiffness, thereby effectively suppressing bending deformation of the ligament 2 in this region.

[0026] Combination Figures 4 to 7 As shown, in another specific implementation, each ligament 2 is provided with multiple circular biomimetic reinforcement nodes 3, and these nodes are evenly spaced along the length of the ligament 2. The evenly spaced arrangement of the circular biomimetic reinforcement nodes 3 makes the stiffness distribution of the ligament 2 more uniform, which is beneficial for achieving stable deformation modes and predictable energy absorption performance. At the same time, the evenly spaced arrangement also facilitates parametric design and performance control. For example, when three circular biomimetic reinforcement nodes 3 are provided on each ligament 2, these three nodes can be placed at the end, middle, and other ends of the ligament 2, respectively, or the nodes can be placed at the locations where reinforcement is most needed based on specific stress analysis results.

[0027] The number of nodes (n), node diameter (d), and distribution location of the circular biomimetic reinforcing nodes 3 are configured as adjustable parameters. By adjusting these parameters, the platform stress, specific energy absorption, and overall load-bearing capacity of the biomimetic reinforced chiral honeycomb structure can be flexibly controlled. For example, in applications prioritizing platform stress, a larger node diameter (d) and a greater number of nodes (n) should be selected to obtain higher platform stress. In applications prioritizing specific energy absorption, a balance needs to be struck between platform stress and added mass, and an appropriate node diameter (d) and number of nodes (n) should be selected to obtain the highest specific energy absorption. In applications sensitive to added mass, a smaller node diameter (d) and a smaller number of nodes (n) should be selected to control the added mass. The distribution location needs to be determined based on the stress characteristics of the ligament 2, and is usually selected in stress concentration areas or locations prone to buckling deformation.

[0028] In another embodiment, this embodiment also provides a design method for a biomimetic enhanced chiral honeycomb structure, the design method comprising the following steps:

[0029] In step S1, the basic geometric parameters of the chiral cellular basic unit are first determined. Specifically, the parameters to be determined include the diameter D of the ring 1, the length L of the ligament 2, the thickness T of the ligament 2, and the width B of the ligament 2. The diameter D of the ring 1 determines the overall size and cell size of the chiral cellular basic unit. The value of the diameter D is typically between 5 mm and 50 mm, with the specific value determined based on the spatial constraints and load-bearing requirements of the application scenario. The length L of the ligament 2 determines the spacing between adjacent rings 1, thus affecting the cell density of the cellular structure. The value of the length L is typically between 10 mm and 100 mm. The thickness T and width B of the ligament 2 determine the cross-sectional shape and basic mechanical properties of the ligament 2. The value of the thickness T is typically between 0.5 mm and 5 mm, and the value of the width B is typically between 1 mm and 10 mm. These parameters need to be initially selected based on the specific application scenario, load-bearing requirements, and lightweight requirements. When selecting these parameters, factors such as the spatial arrangement of the structure, the expected load size, material properties, and the feasibility of the manufacturing process need to be comprehensively considered.

[0030] In step S2, the design parameters of the circular biomimetic reinforcement node 3 are determined based on the target performance indicators. Depending on different application requirements, three different optimization objectives can be selected: one is prioritizing platform stress, the second is prioritizing specific energy absorption, and the third is considering additional mass constraints. When platform stress is the optimization objective, a larger node diameter d (e.g., d is 2 to 4 times the ligament thickness T) and a larger number of nodes n (e.g., 3 to 5 nodes per ligament 2) should be selected to obtain higher platform stress. When specific energy absorption is the optimization objective, a balance needs to be sought between platform stress and additional mass. In this case, the node diameter d is typically 1.5 to 3 times the ligament thickness T, and the number of nodes n is typically 2 to 3 nodes per ligament 2. When additional mass is the constraint, a smaller node diameter d (e.g., d is 1.2 to 2 times the ligament thickness T) and a smaller number of nodes n (e.g., 1 to 2 nodes per ligament 2) should be selected to control the additional mass from exceeding a preset limit. The location of the distribution needs to be determined by finite element analysis or experimental testing based on the stress characteristics of ligament 2. It is usually selected in stress concentration areas or locations where buckling deformation is likely to occur.

[0031] In step S3, the circular biomimetic reinforcing nodes 3 are arranged along the length of the ligament 2, forming a localized reinforcing structure in the ligament 2 that mimics the enlarged nodes of bamboo. Specifically, based on the number of nodes n and their distribution determined in step S2, the center position of each circular biomimetic reinforcing node 3 is determined along the length of the ligament 2. Then, a circular protrusion structure with a diameter d is processed or manufactured, and this protrusion structure is integrally connected to the ligament 2. The circular outline of the circular biomimetic reinforcing node 3 reduces stress concentration and facilitates uniform load transfer. The thickness dimension of the circular biomimetic reinforcing node 3 can be the same as that of the ligament 2, or it can be appropriately increased as needed to further improve local stiffness.

[0032] In step S4, multiple chiral honeycomb basic units containing circular biomimetic reinforcement nodes 3 are periodically arranged to obtain a complete biomimetic reinforced chiral honeycomb structure. The periodic arrangement can be rectangular, rhomboid, or other regular arrangements, depending on the spatial constraints and performance requirements of the application scenario. During the periodic arrangement process, it is necessary to ensure the correct connection relationship between adjacent chiral honeycomb basic units so that the circular biomimetic reinforcement nodes 3 can form an effective force network in the overall structure.

[0033] For example, a specific embodiment of this utility model adopts the following parameter design: the diameter D of the ring 1 is 20mm, the length L of the ligament 2 is 30mm, the thickness T of the ligament 2 is 1.5mm, the width B of the ligament 2 is 4mm, the node diameter d of the circular biomimetic reinforcing node 3 is 4mm, and the number of nodes n is 2 on each ligament 2, distributed at equal intervals along the length of the ligament 2. The biomimetic reinforced chiral honeycomb structure corresponding to this parameter design, when subjected to axial compressive load, exhibits a platform stress that is approximately 45% higher than that of a conventional chiral honeycomb structure, while the added mass only increases by approximately 12%, achieving the optimization goal of obtaining a significant increase in stiffness with a relatively small increase in material volume.

[0034] In this embodiment, the biomimetic reinforced chiral honeycomb structure can be manufactured using various processes. For example, for metallic materials, precision casting can be used. First, a mold with the shape of a circular biomimetic reinforcing node 3 is made. Then, molten metal is poured into the mold and cooled to form an integrated biomimetic reinforced chiral honeycomb structure. Alternatively, CNC machining can be used, where the shapes of the ring 1, ligament 2, and circular biomimetic reinforcing node 3 are machined on a metal sheet by CNC milling or turning. For polymer materials, injection molding or 3D printing can be used. 3D printing is particularly suitable for manufacturing circular biomimetic reinforcing nodes 3 with complex geometries, enabling the integrated molding of the circular biomimetic reinforcing node 3 and ligament 2 without subsequent assembly connections.

[0035] The biomimetic reinforced chiral honeycomb structure of this embodiment also exhibits excellent energy absorption performance under impact loads. When subjected to high-speed impact loads, the circular biomimetic reinforcing nodes 3 absorb impact energy through plastic deformation. Simultaneously, due to their high local stiffness, they can effectively control the propagation speed of deformation waves within the structure, making the energy absorption process more stable and controllable. Compared to ordinary chiral honeycomb structures, the biomimetic reinforced chiral honeycomb structure of this invention can achieve lower peak loads and higher energy absorption efficiency under the same impact energy.

[0036] The biomimetic reinforced chiral honeycomb structure can also be applied to scenarios where bending-dominant deformation occurs. When the structure is subjected to bending loads, the ligament 2 bears bending moments and is prone to bending deformation. Setting circular biomimetic reinforcing nodes 3 on the ligament 2 can effectively improve the bending stiffness of the ligament 2, suppress the occurrence of bending deformation, and thus improve the load-bearing capacity and stiffness of the structure under bending loads.

[0037] In this embodiment of the invention, the reinforcement method does not require combining chiral honeycombs with other complex honeycomb configurations, resulting in a simple structure, lower manufacturing difficulty, and applicability to other bending-dominant honeycomb structures. Compared to hybrid honeycomb or coupled metamaterial structures, this embodiment maintains the basic configuration of the chiral honeycomb structure, achieving performance improvement solely through the addition of biomimetic reinforcement nodes to the ligaments. Therefore, it offers advantages such as simple structure, convenient manufacturing, and low cost. Furthermore, this reinforcement principle can also be applied to other types of bending-dominant honeycomb structures, such as concave honeycombs and Y-shaped honeycombs, demonstrating good versatility and scalability.

[0038] It should be understood that the above are only preferred embodiments of the present utility model, and the protection scope of the present utility model is not limited to the above embodiments. All technical solutions that fall within the scope of the present utility model are protected by the present utility model.

[0039] The accompanying drawings used in the above description of the embodiments only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

Claims

1. A biomimetic enhanced chiral honeycomb structure, comprising a plurality of chiral honeycomb basic units periodically arranged in an in-plane direction, each chiral honeycomb basic unit comprising a ring and a plurality of ligaments connected to the ring, adjacent chiral honeycomb basic units being connected by the ligaments, characterized in that, At least a portion of the ligament is provided with circular biomimetic reinforcement nodes to form a local reinforcement structure for absorbing energy. The diameter of the circular biomimetic reinforcement nodes is larger than the ligament thickness, and the circular biomimetic reinforcement nodes are integrally connected to the ligament.

2. The biomimetic enhanced chiral honeycomb structure according to claim 1, characterized in that, The chiral cellular basic unit includes a ring and four ligaments tangent to the outer circumference of the ring. The four ligaments are equally spaced along the circumference of the ring and are used to connect the rings of adjacent chiral cellular basic units.

3. The biomimetic enhanced chiral honeycomb structure according to claim 1, characterized in that, Each of the ligaments is provided with at least one of the circular biomimetic reinforcement nodes.

4. The biomimetic enhanced chiral honeycomb structure according to claim 3, characterized in that, Each of the ligaments is provided with a number of circular biomimetic reinforcement nodes at equal intervals.

5. The biomimetic enhanced chiral honeycomb structure according to claim 1, characterized in that, The number of nodes, node diameter, and distribution position of the circular biomimetic reinforcement nodes are configured as adjustable parameters to control the platform stress, specific energy absorption, and overall load-bearing capacity of the biomimetic reinforced chiral honeycomb structure.

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